Accepted Manuscript Title: Syringe disposal among people who inject drugs in Los Angeles: The role of sterile syringe source Author: Brendan Quinn Daniel Chu Lynn Wenger Ricky N. Bluthenthal Alex H. Kral PII: DOI: Reference:
S0955-3959(14)00105-4 http://dx.doi.org/doi:10.1016/j.drugpo.2014.05.008 DRUPOL 1389
To appear in:
International Journal of Drug Policy
Received date: Revised date: Accepted date:
18-12-2013 23-4-2014 6-5-2014
Please cite this article as: Quinn, B., Chu, D., Wenger, L., Bluthenthal, R. N., & Kral, A. H.,Syringe disposal among people who inject drugs in Los Angeles: The role of sterile syringe source., International Journal of Drug Policy (2014), http://dx.doi.org/10.1016/j.drugpo.2014.05.008 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
*Highlights (for review)
Syringe disposal among people who inject drugs in Los Angeles: The role of sterile syringe source. Highlights
ce pt
ed
M
an
us
cr
ip t
We examined ‘improper’ syringe disposal among PWID in Los Angeles; Most syringes (83%) were disposed of ‘properly’ or safely (e.g., via SEPs); Sourcing syringes from SEPs decreased the odds of improper disposal; Sourcing syringes from pharmacies increased the odds of improper disposal.
Ac
-
Page 1 of 23
*Manuscript Click here to view linked References
Title: Syringe disposal among people who inject drugs in Los Angeles: The role of sterile syringe source.
Authors: *Brendan Quinn1; PhD, BA(Hons)
ip t
Daniel Chu2 Lynn Wenger3; MSW, MPH
cr
Ricky N. Bluthenthal2; PhD
us
Alex H. Kral3; PhD
an
Author affiliations/institutional addresses: 1
Centre for Population Health, Burnet Institute, 85 Commercial Rd, Melbourne, VIC, 3004, Australia
2
M
Department of Preventive Medicine, Institute for Prevention Research, Keck School of Medicine,
University of Southern California, 2001 N. Soto Street, MC 9239, Los Angeles, CA 90033 3
ed
Urban Health Program, RTI International, 351 California St (Suite 500), San Francisco, CA, 94104,
ce pt
Word Count: 3,353
Ac
*Correspondence: Brendan Quinn
Burnet Institute GPO Box 2284 Melbourne
Victoria, Australia 3001
Phone: +61 3 9282 2259 Fax: +61 3 9282 2138 1
Page 2 of 23
Ac
ce pt
ed
M
an
us
cr
ip t
Email: [email protected]
2
Page 3 of 23
Title: Syringe disposal among people who inject drugs in Los Angeles: The role of sterile syringe source. Authors: Brendan Quinn, Daniel Chu, Lynn Wenger, Ricky N. Bluthenthal, Alex H. Kral
ABSTRACT
ip t
Background: Few recent studies have investigated the prevalence of improperly discarded syringes
cr
in community settings by people who inject drugs (PWID). We examined whether syringe source was associated with the act of improper syringe disposal and amount of syringes improperly disposed of
us
among PWID in Los Angeles, California.
Methods: A cross-sectional sample of PWID (N=412) was recruited and administered a structured
an
questionnaire between July 2011 and April 2013. Descriptive analyses investigated syringe access and disposal practices among participants. Multivariate logistic regression analysis identified adjusted
M
associations between syringe source (syringe exchange program [SEP] or pharmacy) and improper syringe disposal.
ed
Results: Most participants were male (69%), homeless (62%) and low-income earners (64%). The majority (87%) of the sample received syringes from a SEP in the past six months, with 26% having
ce pt
received syringes from pharmacies and 36% from unauthorised sources (e.g., friend, drug dealer). Of more than 30,000 used syringes reportedly disposed of by participants during the past 30 days, 17% were disposed of improperly. Two percent of participants disposed of any used syringes at
Ac
pharmacies, compared to 68% who used SEPs for syringe disposal. Having received sterile syringes from a SEP was independently associated with lower odds of improper syringe disposal; however, purchasing sterile syringes from pharmacies was associated with significantly higher odds of improper syringe disposal. Conclusion: In a city with both SEPs and pharmacies as syringe source and disposal options for PWID, these findings suggest that while pharmacies are selling syringes, they are not as readily involved in safe syringe disposal. Given limits on SEP availability and the large geographic size of Los Angeles County, augmenting current SEP services and providing other community disposal sites,
3
Page 4 of 23
including pharmacy disposal, processes could reduce improper syringe disposal among PWID in Los Angeles.
Ac
ce pt
ed
M
an
us
cr
ip t
Keywords: syringe access, pharmacy, syringe exchange programs
4
Page 5 of 23
INTRODUCTION Recent research estimated that there are over 2,000 community-acquired needlestick injuries in the United States (US) annually, costing the healthcare system $9.8 million each year (Jason, 2013). However, the incidence of blood-borne viral infections (BBVIs) transmitted from needlestick injuries in the community is rare (Papenburg, Blais, Moore, Al-Hosni, Laferriere, Tapiero et al., 2008;
ip t
Thompson, Boughton & Dore, 2003). Regardless of the size of this public health problem, it is
cr
perceived by community members and politicians as a vital concern (Blenkharn, 2008; Green, Martin, Bowman, Mann & Beletsky, 2012; Stopka, Garfein, Ross & Truax, 2007; Treloar & Fraser, 2007;
us
Zavis, 2012). Yet, there have been surprisingly few studies assessing the prevalence of improperly discarded syringes in community settings (e.g., Doherty, Junge, Rathouz, Garfein, Riley & Vlahov,
an
2000; Tookes, Kral, Wenger, Cardenas, Martinez, Sherman et al., 2012; Wenger, Martinez, Carpenter, Geckeler, Colfax & Kral, 2011). People who inject drugs (PWID) are a source for improperly
M
discarded syringes (Bluthenthal, Anderson, Flynn & Kral, 2007). By studying the disposal practices of
ed
PWID, we can learn more about the scope of the problem and propose potential pragmatic solutions.
Syringe exchange programs (SEPs) are a primary means of syringe access and disposal among PWID
ce pt
in the US (Centers for Disease Control and Prevention, 2010; Tookes et al., 2012). The public health benefits of SEPs, including the prevention of BBVI transmission and reduction in risk behaviours, are well-recognised (Hurley, Jolley & Kaldor, 1997; Wodak & Cooney, 2006). Although prior research in
Ac
cities such as Baltimore, New York and San Francisco has indicated that SEP utilisation does not increase improper disposal of used needles (Bluthenthal et al., 2007; Coffin, Latka, Latkin, Wu, Purcell, Metsch et al., 2007; Doherty et al., 2000; Fuller, Ahern, Vadnai, Coffin, Galea, Factor et al., 2002; Sherman, Rusch & Golub, 2004; Tookes et al., 2012), many US cities and states have very few or no official or legal SEPs (amfAR; Green et al., 2012). Even in locations with SEPs, opening hours are often limited (Bluthenthal, Heinzerling, Anderson, Flynn & Kral, 2008; Los Angeles County Department of Public Health), which further impedes proper syringe disposal for PWID (Treloar & Cao, 2005).
5
Page 6 of 23
Another important means of syringe access and disposal among PWID is pharmacies. For example, the New York Expanded Syringe Access Demonstration Program was implemented in 2001 to overcome barriers to SEP utilisation and improve accessibility to, and availability of, syringes for PWID through non-prescription syringe sales at pharmacies (Fuller, Galea, Caceres, Blaney, Sisco & Vlahov, 2007). In studies examining syringe disposal practices, access to sterile syringes was
ip t
generally found to be associated with lower odds of improper syringe disposal (Cleland, Deren,
cr
Fuller, Blaney, McMahon, Tortu et al., 2007; Coffin et al., 2007). However, these studies did not
us
distinguish between types of safe syringe access (i.e., SEPs or pharmacies).
Following the implementation of a similar program in California in 2005, the Disease Prevention
an
Demonstration Project (California Department of Public Health), pharmacies became the second main legal source of syringes in the state in addition to SEPs (Lutnick, Cooper, Dodson, Bluthenthal &
M
Kral, 2013). In their capacity as providers of non-prescription syringes, Californian SEPs and pharmacies are required to provide ‘consumers’ with at least one of three disposal options: onsite
ed
disposal, the provision of sharps containers that satisfy state and federal standards, and/or the provision of mail-back sharps containers (California Department of Public Health). Despite having
ce pt
both SEPs and pharmacies as syringe source and disposal options since 2006, there is a lack of research on syringe access and disposal practices among PWID in Los Angeles.
Ac
We sought to determine the prevalence of syringe disposal by a sample of mostly-marginalised (i.e., low-income, homeless) PWID via SEPs, pharmacies, and improper methods in Los Angeles, the largest city in California. In addition, we examined whether syringe source was associated with improper syringe disposal and amount of syringes improperly disposed.
METHOD Sample The sample was recruited as part of a large National Institute on Drug Abuse (NIDA)-funded mixed methods study examining initiation to injection drug use among PWID in San Francisco and Los 6
Page 7 of 23
Angeles (NIDA grant #R01DA027689). This article focuses exclusively on the Los Angeles participants (recent studies have thoroughly examined syringe disposal in San Francisco (Tookes et al., 2012; Wenger et al., 2011)). Between July 2011 and April 2013, PWID (N=412) were recruited from outreach sites (e.g., drug copping and sales areas, SEPs, drug treatment programs, homeless encampments, free food distribution locations) in Los Angeles neighbourhoods with high numbers of
ip t
PWID. Individuals were eligible to participate in the study if they: 1) were aged 18 years or above; 2)
cr
were able to provide informed consent; and 3) had injected any drug in the past 30 days (as verified
by visual inspection for evidence of recent injecting drug use; i.e., venepuncture marks). Participants
us
were reimbursed $20 for their time and travel expenses. Prior to study implementation, all procedures were reviewed and approved by the Institutional Review Boards at the University of Southern
an
California and RTI International.
M
Questionnaire design and administration
Following the provision of informed consent, study participants were administered a structured
ed
questionnaire designed to collect information on socio-demographic characteristics; mental and physical/general health; current/recent and lifetime drug use patterns, including involvement in risky
ce pt
injecting behaviours; needle/syringe access and disposal practices; and utilisation of drug treatment and other health and support services. Interviews were conducted in private settings at communitybased field sites convenient for participants (e.g., soup kitchens, churches, SEPs). Field sites were
Ac
chosen due to their close proximity to large numbers of PWID in Los Angeles. All questionnaires were interviewer-administered using laptop computers programmed with Questionnaire Design System (QDS) Version 2.6.1 software (Nova Research Company, Bethesda, MD, USA). Interviews lasted a median of approximately 35 minutes (range: 17-90 minutes).
Measures Respondents were asked to list all their sources of syringes during the previous six months. Options included: SEP; syringe distribution program or outreach worker; someone else who visited a SEP; pharmacy; unauthorised source (e.g., street, friend); own prescription for syringes; and shooting 7
Page 8 of 23
gallery or drug dealer. Participants were then asked to identify their primary source of syringes during the last six months.
Participants who reported disposing of used syringes in the past 30 days were asked to list their means of syringe disposal, including: returning them to a SEP; having someone else return them to a SEP;
ip t
selling or giving them away; putting them in the trash; flushing them down a toilet; leaving them in a
cr
public place (e.g., street, sidewalk, park, parking lot); taking them to a hospital or clinic; taking them to a pharmacy; putting them in a public biohazard waste container; having them confiscated by police;
us
or employing any other method of syringe disposal. ‘Improper’ syringe disposal was classified according to the definition outlined in previous research which compared syringe disposal practices
an
among PWID in a city with, versus a city without, SEPs (Bluthenthal et al., 2007; Tookes et al., 2012); i.e., disposal of used syringes by: selling or giving them away; leaving them in a public place;
M
putting them in the trash; flushing them down a toilet; or leaving in a sewer, manhole or gutter. Alternatively, ‘proper’ syringe disposal was classified as: returning syringes to a SEP; having
ed
someone else (e.g., partner, peer) return syringes to a SEP; putting them in a public biohazard waste container; having them confiscated by police; or returning them to a pharmacy. Participants were
ce pt
asked to specify how many syringes were disposed of via each method. Participants were categorised as having improperly disposed of most of their syringes when they reported that the total number of syringes disposed of via improper means was more than 50% of the total number of syringes disposed
Ac
of via all disposal methods.
Design and statistical analysis Descriptive analyses (e.g., frequencies, medians) were used to examine participant characteristics, drug use patterns and risk behaviours, in addition to syringe access and disposal practices. Bivariate analyses identified unadjusted associations between potential confounding variables and syringe source [SEP or pharmacy (with or without prescription)] and improper syringe disposal outcomes (i.e., improperly disposed of any syringes in the past 30 days, improperly disposed of most syringes in that time). Bivariate analysis methods included the Mantel Haenszel Chi-square and Fisher’s exact 8
Page 9 of 23
tests for categorical variables and the Wilcoxon signed-rank test for continuous variables. In multivariate logistic regression analysis, a stepwise backwards elimination process controlling for potential confounders, and forcing syringe source as exposure variables, identified adjusted associations with improper syringe disposal. All data analyses were conducted using Stata Version
ip t
13.0 (Statacorp LP, Texas, USA) with a significance level of p50%) of their syringes during that time (27% vs. 73%; p
S0955-3959(14)00105-4 http://dx.doi.org/doi:10.1016/j.drugpo.2014.05.008 DRUPOL 1389
To appear in:
International Journal of Drug Policy
Received date: Revised date: Accepted date:
18-12-2013 23-4-2014 6-5-2014
Please cite this article as: Quinn, B., Chu, D., Wenger, L., Bluthenthal, R. N., & Kral, A. H.,Syringe disposal among people who inject drugs in Los Angeles: The role of sterile syringe source., International Journal of Drug Policy (2014), http://dx.doi.org/10.1016/j.drugpo.2014.05.008 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
*Highlights (for review)
Syringe disposal among people who inject drugs in Los Angeles: The role of sterile syringe source. Highlights
ce pt
ed
M
an
us
cr
ip t
We examined ‘improper’ syringe disposal among PWID in Los Angeles; Most syringes (83%) were disposed of ‘properly’ or safely (e.g., via SEPs); Sourcing syringes from SEPs decreased the odds of improper disposal; Sourcing syringes from pharmacies increased the odds of improper disposal.
Ac
-
Page 1 of 23
*Manuscript Click here to view linked References
Title: Syringe disposal among people who inject drugs in Los Angeles: The role of sterile syringe source.
Authors: *Brendan Quinn1; PhD, BA(Hons)
ip t
Daniel Chu2 Lynn Wenger3; MSW, MPH
cr
Ricky N. Bluthenthal2; PhD
us
Alex H. Kral3; PhD
an
Author affiliations/institutional addresses: 1
Centre for Population Health, Burnet Institute, 85 Commercial Rd, Melbourne, VIC, 3004, Australia
2
M
Department of Preventive Medicine, Institute for Prevention Research, Keck School of Medicine,
University of Southern California, 2001 N. Soto Street, MC 9239, Los Angeles, CA 90033 3
ed
Urban Health Program, RTI International, 351 California St (Suite 500), San Francisco, CA, 94104,
ce pt
Word Count: 3,353
Ac
*Correspondence: Brendan Quinn
Burnet Institute GPO Box 2284 Melbourne
Victoria, Australia 3001
Phone: +61 3 9282 2259 Fax: +61 3 9282 2138 1
Page 2 of 23
Ac
ce pt
ed
M
an
us
cr
ip t
Email: [email protected]
2
Page 3 of 23
Title: Syringe disposal among people who inject drugs in Los Angeles: The role of sterile syringe source. Authors: Brendan Quinn, Daniel Chu, Lynn Wenger, Ricky N. Bluthenthal, Alex H. Kral
ABSTRACT
ip t
Background: Few recent studies have investigated the prevalence of improperly discarded syringes
cr
in community settings by people who inject drugs (PWID). We examined whether syringe source was associated with the act of improper syringe disposal and amount of syringes improperly disposed of
us
among PWID in Los Angeles, California.
Methods: A cross-sectional sample of PWID (N=412) was recruited and administered a structured
an
questionnaire between July 2011 and April 2013. Descriptive analyses investigated syringe access and disposal practices among participants. Multivariate logistic regression analysis identified adjusted
M
associations between syringe source (syringe exchange program [SEP] or pharmacy) and improper syringe disposal.
ed
Results: Most participants were male (69%), homeless (62%) and low-income earners (64%). The majority (87%) of the sample received syringes from a SEP in the past six months, with 26% having
ce pt
received syringes from pharmacies and 36% from unauthorised sources (e.g., friend, drug dealer). Of more than 30,000 used syringes reportedly disposed of by participants during the past 30 days, 17% were disposed of improperly. Two percent of participants disposed of any used syringes at
Ac
pharmacies, compared to 68% who used SEPs for syringe disposal. Having received sterile syringes from a SEP was independently associated with lower odds of improper syringe disposal; however, purchasing sterile syringes from pharmacies was associated with significantly higher odds of improper syringe disposal. Conclusion: In a city with both SEPs and pharmacies as syringe source and disposal options for PWID, these findings suggest that while pharmacies are selling syringes, they are not as readily involved in safe syringe disposal. Given limits on SEP availability and the large geographic size of Los Angeles County, augmenting current SEP services and providing other community disposal sites,
3
Page 4 of 23
including pharmacy disposal, processes could reduce improper syringe disposal among PWID in Los Angeles.
Ac
ce pt
ed
M
an
us
cr
ip t
Keywords: syringe access, pharmacy, syringe exchange programs
4
Page 5 of 23
INTRODUCTION Recent research estimated that there are over 2,000 community-acquired needlestick injuries in the United States (US) annually, costing the healthcare system $9.8 million each year (Jason, 2013). However, the incidence of blood-borne viral infections (BBVIs) transmitted from needlestick injuries in the community is rare (Papenburg, Blais, Moore, Al-Hosni, Laferriere, Tapiero et al., 2008;
ip t
Thompson, Boughton & Dore, 2003). Regardless of the size of this public health problem, it is
cr
perceived by community members and politicians as a vital concern (Blenkharn, 2008; Green, Martin, Bowman, Mann & Beletsky, 2012; Stopka, Garfein, Ross & Truax, 2007; Treloar & Fraser, 2007;
us
Zavis, 2012). Yet, there have been surprisingly few studies assessing the prevalence of improperly discarded syringes in community settings (e.g., Doherty, Junge, Rathouz, Garfein, Riley & Vlahov,
an
2000; Tookes, Kral, Wenger, Cardenas, Martinez, Sherman et al., 2012; Wenger, Martinez, Carpenter, Geckeler, Colfax & Kral, 2011). People who inject drugs (PWID) are a source for improperly
M
discarded syringes (Bluthenthal, Anderson, Flynn & Kral, 2007). By studying the disposal practices of
ed
PWID, we can learn more about the scope of the problem and propose potential pragmatic solutions.
Syringe exchange programs (SEPs) are a primary means of syringe access and disposal among PWID
ce pt
in the US (Centers for Disease Control and Prevention, 2010; Tookes et al., 2012). The public health benefits of SEPs, including the prevention of BBVI transmission and reduction in risk behaviours, are well-recognised (Hurley, Jolley & Kaldor, 1997; Wodak & Cooney, 2006). Although prior research in
Ac
cities such as Baltimore, New York and San Francisco has indicated that SEP utilisation does not increase improper disposal of used needles (Bluthenthal et al., 2007; Coffin, Latka, Latkin, Wu, Purcell, Metsch et al., 2007; Doherty et al., 2000; Fuller, Ahern, Vadnai, Coffin, Galea, Factor et al., 2002; Sherman, Rusch & Golub, 2004; Tookes et al., 2012), many US cities and states have very few or no official or legal SEPs (amfAR; Green et al., 2012). Even in locations with SEPs, opening hours are often limited (Bluthenthal, Heinzerling, Anderson, Flynn & Kral, 2008; Los Angeles County Department of Public Health), which further impedes proper syringe disposal for PWID (Treloar & Cao, 2005).
5
Page 6 of 23
Another important means of syringe access and disposal among PWID is pharmacies. For example, the New York Expanded Syringe Access Demonstration Program was implemented in 2001 to overcome barriers to SEP utilisation and improve accessibility to, and availability of, syringes for PWID through non-prescription syringe sales at pharmacies (Fuller, Galea, Caceres, Blaney, Sisco & Vlahov, 2007). In studies examining syringe disposal practices, access to sterile syringes was
ip t
generally found to be associated with lower odds of improper syringe disposal (Cleland, Deren,
cr
Fuller, Blaney, McMahon, Tortu et al., 2007; Coffin et al., 2007). However, these studies did not
us
distinguish between types of safe syringe access (i.e., SEPs or pharmacies).
Following the implementation of a similar program in California in 2005, the Disease Prevention
an
Demonstration Project (California Department of Public Health), pharmacies became the second main legal source of syringes in the state in addition to SEPs (Lutnick, Cooper, Dodson, Bluthenthal &
M
Kral, 2013). In their capacity as providers of non-prescription syringes, Californian SEPs and pharmacies are required to provide ‘consumers’ with at least one of three disposal options: onsite
ed
disposal, the provision of sharps containers that satisfy state and federal standards, and/or the provision of mail-back sharps containers (California Department of Public Health). Despite having
ce pt
both SEPs and pharmacies as syringe source and disposal options since 2006, there is a lack of research on syringe access and disposal practices among PWID in Los Angeles.
Ac
We sought to determine the prevalence of syringe disposal by a sample of mostly-marginalised (i.e., low-income, homeless) PWID via SEPs, pharmacies, and improper methods in Los Angeles, the largest city in California. In addition, we examined whether syringe source was associated with improper syringe disposal and amount of syringes improperly disposed.
METHOD Sample The sample was recruited as part of a large National Institute on Drug Abuse (NIDA)-funded mixed methods study examining initiation to injection drug use among PWID in San Francisco and Los 6
Page 7 of 23
Angeles (NIDA grant #R01DA027689). This article focuses exclusively on the Los Angeles participants (recent studies have thoroughly examined syringe disposal in San Francisco (Tookes et al., 2012; Wenger et al., 2011)). Between July 2011 and April 2013, PWID (N=412) were recruited from outreach sites (e.g., drug copping and sales areas, SEPs, drug treatment programs, homeless encampments, free food distribution locations) in Los Angeles neighbourhoods with high numbers of
ip t
PWID. Individuals were eligible to participate in the study if they: 1) were aged 18 years or above; 2)
cr
were able to provide informed consent; and 3) had injected any drug in the past 30 days (as verified
by visual inspection for evidence of recent injecting drug use; i.e., venepuncture marks). Participants
us
were reimbursed $20 for their time and travel expenses. Prior to study implementation, all procedures were reviewed and approved by the Institutional Review Boards at the University of Southern
an
California and RTI International.
M
Questionnaire design and administration
Following the provision of informed consent, study participants were administered a structured
ed
questionnaire designed to collect information on socio-demographic characteristics; mental and physical/general health; current/recent and lifetime drug use patterns, including involvement in risky
ce pt
injecting behaviours; needle/syringe access and disposal practices; and utilisation of drug treatment and other health and support services. Interviews were conducted in private settings at communitybased field sites convenient for participants (e.g., soup kitchens, churches, SEPs). Field sites were
Ac
chosen due to their close proximity to large numbers of PWID in Los Angeles. All questionnaires were interviewer-administered using laptop computers programmed with Questionnaire Design System (QDS) Version 2.6.1 software (Nova Research Company, Bethesda, MD, USA). Interviews lasted a median of approximately 35 minutes (range: 17-90 minutes).
Measures Respondents were asked to list all their sources of syringes during the previous six months. Options included: SEP; syringe distribution program or outreach worker; someone else who visited a SEP; pharmacy; unauthorised source (e.g., street, friend); own prescription for syringes; and shooting 7
Page 8 of 23
gallery or drug dealer. Participants were then asked to identify their primary source of syringes during the last six months.
Participants who reported disposing of used syringes in the past 30 days were asked to list their means of syringe disposal, including: returning them to a SEP; having someone else return them to a SEP;
ip t
selling or giving them away; putting them in the trash; flushing them down a toilet; leaving them in a
cr
public place (e.g., street, sidewalk, park, parking lot); taking them to a hospital or clinic; taking them to a pharmacy; putting them in a public biohazard waste container; having them confiscated by police;
us
or employing any other method of syringe disposal. ‘Improper’ syringe disposal was classified according to the definition outlined in previous research which compared syringe disposal practices
an
among PWID in a city with, versus a city without, SEPs (Bluthenthal et al., 2007; Tookes et al., 2012); i.e., disposal of used syringes by: selling or giving them away; leaving them in a public place;
M
putting them in the trash; flushing them down a toilet; or leaving in a sewer, manhole or gutter. Alternatively, ‘proper’ syringe disposal was classified as: returning syringes to a SEP; having
ed
someone else (e.g., partner, peer) return syringes to a SEP; putting them in a public biohazard waste container; having them confiscated by police; or returning them to a pharmacy. Participants were
ce pt
asked to specify how many syringes were disposed of via each method. Participants were categorised as having improperly disposed of most of their syringes when they reported that the total number of syringes disposed of via improper means was more than 50% of the total number of syringes disposed
Ac
of via all disposal methods.
Design and statistical analysis Descriptive analyses (e.g., frequencies, medians) were used to examine participant characteristics, drug use patterns and risk behaviours, in addition to syringe access and disposal practices. Bivariate analyses identified unadjusted associations between potential confounding variables and syringe source [SEP or pharmacy (with or without prescription)] and improper syringe disposal outcomes (i.e., improperly disposed of any syringes in the past 30 days, improperly disposed of most syringes in that time). Bivariate analysis methods included the Mantel Haenszel Chi-square and Fisher’s exact 8
Page 9 of 23
tests for categorical variables and the Wilcoxon signed-rank test for continuous variables. In multivariate logistic regression analysis, a stepwise backwards elimination process controlling for potential confounders, and forcing syringe source as exposure variables, identified adjusted associations with improper syringe disposal. All data analyses were conducted using Stata Version
ip t
13.0 (Statacorp LP, Texas, USA) with a significance level of p50%) of their syringes during that time (27% vs. 73%; p
